The advantages of communicating by modulated light waves over an optical fiber medium are now well recognized. Such a system is described, for example, in the article by E. A. J. Marcatili and T. Li, "Research on Optical Fiber Transmission," appearing in the Bell Labs Record of December 1971, pages 331-338.
For use as communications paths in the telephone plant, the optical fibers must be grouped for ease of handling and placement. Suitable forms of optical communication cable structures as well as splicing schemes, are indeed critical to a functioning system. One possible building block for an optical communication cable is a fiber ribbon structure which, because of its two-dimension nature, simplifies aligning of the fiber ends to accomplish mass field splicing. The optical fiber ribbon also provides mechanical support and protection. The ribbon structure, by totally enclosing the fibers, can additionally reduce mechanical abrasion and risk of exposure to moisture and other ambient hazards.
Any ribbon structure, however, must especially lend itself readily to simple splicing techniques. Indeed, it is difficult to separate the considerations of ribbon structure and splice structure.
Ideally, an optical communications cable splice should have certain specific features. Gang connection of many or all paths at a time should be reliably possible. Furthermore, the splice should generate as little crosstalk as possible. Also, a splice that does not add excessively to the cross-sectional diameter can reduce or eliminate the cost of splice closures. Of course, any splice must have a minimum of loss and a maximum of simplicity from a craftsman's standpoint.
Accordingly, a principal inventive object is to realize an optical fiber ribbon structure that is especially amenable to splicing.
A second inventive object is to realize an optical fiber ribbon structure that is simple to manufacture.
A specific inventive object is to devise an optical fiber ribbon structure which can be spliced without need of precision alignment and without adding excessive bulk to the ribbon at the splice point.
A further specific object is to devise an optical fiber ribbon structure and related splicing technology and apparatus which is simple for the craftsman in the field to use.